Electronic-tube socket contact



June 19, 1951 w. l. INGHAM ELECTRONIC TUBE SOCKET CONTACT Filed Sept. 21, 1949 INVENTOR. WILLIAM \RVYIN INGHAM Patented June I9, 1951 Application September 21, 1949, Serial No. 116,903

NT FFlCE 2 Claims.

My invention relates to electrical contacts and more particularly to a contact adaptable for a socket designed to receive an electronic tube. This application is a continuation of my ccpending application, Serial No. 664,767, filed April 25, 1946, now abandoned.

While heretofore, sockets having tub'ular contact elements for receiving the pins of electronic tubes have been employed, it has been found that with repeated use, poor electrical contact be-= tween the contact element and the tube pin often results, due generally to the fact that the metal comprising the contact element spreads to such extent that no electrical contact exists or at least an unsatisfactory contact is established between the contact element and the tube pin.

For example, for one type of tube, radio manufacturers have required that the tube socket be rovidecl with contact elements each capable of supporting a 0.090 inch diameter pin having a 3 ounce weight suspended upon it after a 0.096" diameter pin has been inserted and removed ten times from the contact element.

With the contact element of my invention, I am able to meet the requirements hereinbefore set forth so that after many times ten insertions of a 0.096" diameter pin in its socketcontact element, the latter will still support such pin even when weighted with ounces instead of the aforementioned specified test weight of only 3 ounces.

It is further to be pointed out that the pins on the radio tubes have an inherent diametric tolerance of plus or minus 0.002". For example, for

receiving and supporting therein a tube pin having the diametric variations above noted, such element being so designed as to permit frequent insertion and removal of the tube pin into and out of contact element without overstressing the same and so reducing or otherwise impairing its capability for making proper electrical contact with the tube pin inserted therein.

Another object of my invention is to provide high pressure points of contact or low contact resistance between the pin and an electrical conducting socket contact.

Another object of my invention is to provide a wiping contact between a tube socket and tube which will remove any severe oxide or other contaminations, which otherwise would result in high resistance contact.

Other objects of my invention are to provide an improved device of the character described, that is easily and economically produced, which is sturdy in construction, and which is highly efficient in operation.

With the above and related objects in View, my invention consists in the details of construction and combination of parts, as will be more fully understood from the following description, when read in conjunction with the accompanying drawing in which:

Fig. 1 is a perspective view of a socket contact sleeve in association with the prong or pin of an electronic tube;

Fig. 2 is a rear view sleeve per se;

Fig. 3 is a side View of the socket contact of the socket contact a 0.093 pin the diameter limits of the pin are e e; a d 0.091" to 0.095". The tube manufacturers, how- Fi 4 i a op pl n v w as ak n al n h line ever, have commercial reasons for guaranteeing of their tolerances to plus or minus 0.003", and thus such manufacturers will accept as a 0.093" pin one having a diameter variation of from 0.090" to 0.096". While a 0.093" pin is commercially made within the tolerance limits of 0.091 and 0.095" as previously explained, the actual pin diameter is soon increased approx- Referring now in greater detail to the drawing wherein similar reference characters refer to similar parts, I show a pressed metal electrical contact sleeve or pin contactor, generally designated as A, a plurality of which are adapted to be mounted in any suitable manner upon the supporting socket for an electronic tube having imately 0001" due to a coating film of solder or pron s r pi u a r sp v l n toxide, so that the actual diameter of the tube a l n h l v on a t members of the pin or prong ranges between 0.091 to 0.096" socket. Each sleeve contact member A is after the tubes come from the tube manufacturing plant and wires are soldered to the bottom of each such pin or prong. The variation of tube pins described in the aforementioned example is correspondingly applicable to pins of other diametrical sizes.

It is, therefore, an object of my invention to provide a contact element capable of satisfactorily adapted to receive the pin of an electronic tubepin, whereby the tube will be mechanically supported by the socket and the pins on the tube will be electrically engaged by the sleeves on the socket.

The electrical contact sleeve A is formed of electrically conductive sheet metal which is preferably suitably coated to render it non-corrosive,

The socket A is formed to provide a longitudinally split, generally tubular upper section A and an arcuately shaped lower section A transversely curved to the same wall curvature as that of the upper section A The upper tubular section A is provided along the longitudinal line of its split with a pair of laterally spaced longitudinally extending edge portions 14 and I6 which are respectively flattened and disposed in angularly related intersecting planes extending chordally across minor parts of the full circumference of said tubular section A These angularly related flattened portions I l and I6 are'respectively provided with longitudinally extending parallel. edges l0 and I2 and constitute in eliect, a pair of resilient wing-like elements which serve conjointly with the circular portion of the tubular section A to engage the tube pin B at three circumferentially spaced points. In order to provide for maximum contact pressure at said three points of contact and to insurev maximum spring of the flattened wing-like portions. 14 and IS, the tubular section A is circumferentially restricted to provide an internal bead 20. adjacent the entrance and it of the sleeve contactA, this bead being extended to and through the flattened portions it and 16 thereof.

It will be noted that by virtue of the inturned. flattened portions i4. and 16, the tube pin B represented by dotted lines in Figure 4, is engaged by the internal bead 29 at three circumferentially spaced pressure points.

The internal bead 20- not only reinforces and strengthens the contact sleeve against its being overstressed beyond the elastic limit of the sheet material of which it is formed, but also provides points of contact for the tube pin, which are of lower electrical resistance than would be. the case were the pin in elongated line or surface contact with the sleeve. Also, the circumferentially spaced point contacts permit the tube pin to rock within or assume a non-coaxial relation with respect to the contact sleeve without reducing the efficiency of the electrical connection between the pin and its contact sleeve, at the same time that they present high pressure wiping contacts for removal of severe oxide or other such surface contamination as might result inexcessive. resistance against passage of current through the connection between the pin and its contact sleeve.

There is an extension or terminal 22 integrally formed at the lower end of the sleeve which may have hooked sides 26 so that an electric wire or conductor may be attached thereto, and there also may be an eye or opening in the terminal 2.4 end for receiving an electrical conductor. The number of sleeves which are installed on a tube socket will depend upon the number of pins or prongs on the tube, and in the case of a lock-in or an octal socket the number of pins may be eight in number.

The split tubular portion A of the contact sleeve A fits into a circular opening suitably formed in the insulating base of the socket while its arcuately shaped portion A which normally projects beyond the lower surface of the; socket base, may be indented so that it will engage said lower surface of the socket base in order that the sleeve will not be pulled from said base.

Although my invention has been described in considerable detail, such description is intended as being illustrative rather than limiting, since the invention maybe variously embodied, and the scope. of the invention is to be determined as claimed.

What is claimed to be new and useful is:

1. A sleeve-type contact element for an electronic tube socket comprising a one-piece sheet metal part stamped and rolled to provide a generally tubular section for receiving 1e contact pin of an electronic tube, said tubular section being longitudinally split to provide it with a pair of laterally spaced longitudinally extending edge portions, the laterally spaced edge portions being respectively flattened and disposed in angularly related intersecting planes extending chordally across a minor part of the full circumierence of said tubular section, said tubular section, including its laterally spaced flattened edge portions, having an internal circumferential bead providing three tangential contacts with a tube contact pin inserted into the tubular section of said contact element.

2. In a sleeve-type contact element as defined in claim 1 wherein said internal bead is located adjacent the entrance end of said split tubular section and wherein the latter section is provided with a terminal extension in longitudinal continuation of the arcuate, unsplit portion of said tubular section.

WILLIAM IRWIN INGHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,017,940 Bessey Oct. 22, 1935 2,211,726. Knutson Aug. 13, 1940 2,269,605 Smith Jan. 13, 1942 FOREIGN PATENTS Number Country Date 381,393 England Oct. 6, 1932 471,375 France Oct. 24, 1914 559,579 England Feb. 24, 1944 

